Multi-acting Anti-swabbing Fluid Loss Control Valve

ABSTRACT

The multi-acting valve design features an outer collet around a mandrel with the collet spring biased to a first position where one set of flow ports on one side of a seat with a captive ball can be closed so that the valve acts to prevent fluid loss. When the collet engages a profile and the mandrel is set down the ports above and below the seated ball allow a bypass path around the central path of the mandrel where the ball is seated on a seat. The ports above and below the seated ball communicate into an annular space provided by a sleeve around the mandrel that is supported by the collet assembly that finds temporary support on a profile in a surrounding tubular. The mandrel has an exterior detent to selectively hold the bypass open when the collet assembly is landed on another support to advance it above the mandrel detent.

FIELD OF THE INVENTION

The field of this invention relates to valves in subterranean use and more particularly in systems for fracturing and gravel packing systems where the valve can serve as a fluid loss control valve that has the capability to also prevent swabbing as an inner string is removed from a subterranean isolation packer.

BACKGROUND OF THE INVENTION

Many completions involve fracturing the formation by pumping fluid under pressure into the formation and closing off a return path to the surface. Typically a gravel packing assembly is used to not only accomplish the fracturing but to also locate an isolation packer that supports screens and an inner string that can be manipulated with respect to the isolation packer after the isolation packer is set. The packer assembly supports a crossover tool that is used to deliver gravel down an inner string and have it cross over below the set packer into a lower annulus outside the screen assembly. The gravel is deposited in the lower annulus and fluid that transports the gravel goes through the screen and back into the crossover to reach the surface in the upper annulus above the set packer.

The inner string typically includes a fluid loss control valve which in the past has been a ball on a seat or a flapper type valve. This valve minimizes fluid loss to the formation during fracturing or gravel packing. The problem with such valves is that when they are actuated to perform their intended purpose such as by releasing a flapper to close or are always active such as a ball on seat, and the inner string is picked up for a completion procedure or for removal from the packer the result is swabbing the well. Swabbing is a term given to the phenomenon of reducing well pressure by removal of a tool generally in applications where the tool being removed does not allow flow around itself making the picking up an event that tries to draw fluid from the formation. This phenomenon affects the subsequent formation productivity so that its occurrence is not desirable.

What is desirable in a fluid loss control valve is that it prevents swabbing in one mode while still enabled to act as a fluid loss control valve. Another feature is that it can be used to administer treatment fluid such as acid into the screens as the inner string is removed from the screen assembly.

In the past a ball on seat type of shifting mechanism for the orientation of a crossover tool had the seat integrated into a sliding sleeve so that when a retainer for the sleeve was broken with applied pressure on the seated ball, the sleeve would shift and expose a bypass passage around the seated ball so that acid could be pumped as the inner string was removed. Such a design is illustrated in U.S. Pat. No. 6,702,020. Yet other references provide the basics of crossover systems and their use of fluid loss control valves, such as: U.S. Pat. No. 6,983,796; 6,932,156; 6,789,623; 6,702,020; 6,382,319; 6,230,803; 6,230,801; 5,746,274.

Prior flapper type fluid loss control valves would prevent swabbing when held open but once deployed no longer had the ability to prevent swabbing on string removal. Additionally, if fluid needs to be placed below the flapper valve, such as spotting acid inside of screens, the flow would be restricted through an orifice in the flapper since these types of valves generally are not multi-acting.

A multi-acting fluid loss control valve of the present invention addresses the need to prevent swabbing while still having a functional fluid loss control ability. In one embodiment a captive ball is provided adjacent an associated seat. The ball functions for fluid loss control when seated on the seat and a bypass of the seated ball is also a function of the assembly so that swabbing is prevented while also making fluid injection such as acid possible on string removal. The valve can also be other types than a ball on a seat such as a flapper with the selective feature allowing the flapper to be cammed open or closed as needed at any given time to perform the desired function. Those skilled in the art will further understand more aspects of the invention from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined by the appended claims.

SUMMARY OF THE INVENTION

The multi-acting valve design features an outer collet around a mandrel with the collet spring biased to a first position where one set of flow ports on one side of a seat with a captive ball can be closed so that the valve acts to prevent fluid loss. When the collet engages a profile and the mandrel is set down the ports above and below the seated ball allow a bypass path around the central path of the mandrel where the ball is seated on a seat. The ports above and below the seated ball communicate into an annular space provided by a sleeve around the mandrel that is supported by the collet assembly that finds temporary support on a profile in a surrounding tubular. The mandrel has an exterior detent to selectively hold the bypass open when the collet assembly is landed on another support to advance it above the mandrel detent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a section view of the preferred embodiment in a picked up position where the bypass for the seated ball is closed;

FIG. 2 is the view of FIG. 1 in a set down position with the exterior collet assembly supported to open the bypass around the seated ball;

FIG. 3 is the view of FIG. 2 with the bypass held open after setting down a distance sufficient to get the collet assembly above an external travel stop on the mandrel;

FIG. 4 is an alternative embodiment shown in section when picked up so that the bypass on the seated ball is open;

FIG. 4 a is an outside view of the section view shown in FIG. 4;

FIG. 5 is the view of FIG. 4 with the collet assembly supported and weight set down to close the bypass for the seated ball; and

FIG. 5 a is an outside view of the section view shown in FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates the valve 10 that interacts with a tubular string 12 that has a recess 14 whose purpose will be explained below. A mandrel 16 has a through passage 18 that is surrounded by a ball seat 20 that has a ball 22 that is retained from being blown up the passage 18 by a retainer rod or similar device 24 that spans across the passage 18. The ball 22 is able to move off the seat 20 when there is more pressure below the ball 22 than above it. In those instances the rod 24 defines the travel limit of the ball 22. Thus the ball 22 with the seat 20 functions like a check valve allowing uphole flow with a bypass capability that can be selectively opened or closed.

A collet or outer assembly 26 surrounds the mandrel 16 in a way that relative axial movement between them is possible. The collet assembly is shaped as an annular cylinder with a series of spaced fingers 28 extending between upper end ring 30 and lower end ring 32. An internal recess 34 is adjacent the lower end ring 32. Recess 34 has an upper end 36 and a lower end 38. A travel stop 40 in the form of an exterior ring on the mandrel 16 travels between ends 36 and 38 during normal operation. FIG. 2 illustrates the collet assembly 26 having an exterior dog 42 landed in groove 14 of the tubular 12 so that the collet assembly stops moving as the mandrel 16 is lowered so that the travel stop 40 has moved down to the lower end 38 of the groove 34.

Upper bypass ports 44 are shown in FIG. 1 between spaced seals 46 and 48 so that they are effectively closed. Bypass sleeve 50 has end seals 52 and 54 that between them define a surrounding annular space 56 that is shown in FIG. 1 to be in fluid communication with lower bypass ports 58. Spring 60 pushes off of flange 62 to bias the collet assembly 26 in a down direction toward contact with sleeve 64 below. Sleeve 64 is supported on the mandrel 16.

In the FIG. 1 position the valve assembly is not landed on any shoulders and is in essence suspended or being picked up. In this position there is no flow around the seated ball 22 in a direction from upper ports 44 to lower ports 58 through the passage 56 because the ports 44 are between seals 46 and 48. In certain operations in a well it will be desirable to keep the valve closed such as when gravel is directed to a crossover to exit into a lower annulus and the intention is to fracture the formation. In those occasions there will be pressure applied down on the seated ball 22 to put it firmly on the seat 20 to close the passage 18 with no bypass possible around the ball 22. This can happen during a reversing out procedure where flow down passage 18 is not wanted so that the excess gravel can be reversed out to a surface through tubing that is above valve 10.

At other times there can be a need to determine or monitor the pressures beyond the ball 22 or to deliver fluid past the ball 22 and for those occasions the collet assembly 26 is supported by putting dog 42 in groove 14 and setting down weight on the mandrel 16 just to the point of getting the upper ports 44 past seals 48 and 52 and into annular space 56 so that the seated ball 22 can be bypassed with flow going from ports 44 to 58 as shown in FIG. 2.

FIG. 3 illustrates another feature of the valve assembly 10. To get into this position the collet assembly 26 is initially supported in groove 14 and the mandrel 16 is set down far enough to get the travel stop 40 to go past or under the lower end ring 32 as the spring 60 is compressed. Spring 60 is sized to hold the collet assembly 26 to the stop 40 which allows bypass flow around seated ball 22 from ports 44 to ports 58 so that the valve assembly 10 can be removed without swabbing the well. On the way out the dogs 42 just jump out of groove 14 and the relative positions of the collet assembly 26 and the mandrel 14 are maintained. It should be noted that the valve assembly 10 can go back and forth between the FIGS. 1 and 2 positions using picking up and setting down weight but if a certain amount of relative motion occurs when setting down weight that gets the travel stop 40 out of groove 34 and beyond the lower end ring 32 then the FIG. 3 position will be maintained. In any event of picking up the valve assembly 10 it will not swab with the difference between FIGS. 2 and 3 being that the bypass around ball 22 can be closed in the FIG. 2 position but stays open in the FIG. 3 position.

FIGS. 4 and 5 illustrate a similar design with the difference being that without the valve assembly 100 being set down, there is always an open bypass around the ball 102 seated on seat 104 starting in passage 106 at upper ports 108, continuing through annular passage 110 and back in through ports 112. With no weight set down the spring 114 pushes down on collet assembly 116 to position sleeve 118 so that seals 120 and 122 straddle both ports 108 and 112. As shown in FIG. 5, when dogs 124 are put into groove 126 and weight is set down, the lower ports 112 go between seals 128 and 130 in lower end ring 132 and the bypass around the seated ball 102 is closed. Thus for example, when reversing out gravel, the FIGS. 4 and 5 embodiment will need to be set down as opposed to the preferred embodiment in FIG. 1 where the bypass on the ball is closed in a picked up condition of the valve assembly 10.

Those skilled in the art will appreciate that the illustrated valve assembly has the ability to hold a passage closed and under predetermined conditions allow it to open around a valve member with the preferred embodiment providing a way of switching back and forth between closed and bypass positions until set down mandrel movement of a predetermined distance holds the valve assembly in the bypass position so that its removal will not swab a well.

The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below. 

1. A valve for subterranean use in a well, comprising: a mandrel having a passage therethrough and an upper end and a lower end for connection to a tubular string; a valve member in said passage; an outer assembly mounted to said mandrel for relative movement therebetween and defining a bypass flow path around said valve member located outside said passage and extending from ports in said passage; said relative movement selectively opening and closing said bypass passage.
 2. The valve of claim 1, wherein: said relative movement is caused by engaging said outer assembly on a support in the well.
 3. The valve of claim 2, wherein: said bypass flow path is open until said outer assembly is landed on the support.
 4. The valve of claim 2, wherein: said valve member comprising a seat in said passage and an object that obstructs said passage when landed on said seat.
 5. The valve of claim 4, wherein: said object is retained by a retainer in said passage when separated from said seat responsive to flow from the lower end toward the upper end of said passage.
 6. The valve of claim 5, wherein: said object is a ball or a flapper.
 7. The valve of claim 1, wherein: said outer assembly further comprising spaced seals in contact with said mandrel and straddling at least one of said ports located on one side of said valve member when said bypass flow path is closed.
 8. The valve of claim 1, wherein: said mandrel comprises a travel stop for said outer assembly; said outer assembly movable to open and close said bypass flow path without engaging said travel stop, whereupon relative movement exceeding a predetermined value said travel stop retains said bypass flow path open.
 9. The valve of claim 8, wherein: said relative movement is caused by engaging said outer assembly on a support in the well; said bypass flow path remaining open after relative movement that exceeds a predetermined value despite subsequent engagement of said outer assembly on the support.
 10. The valve of claim 9, wherein: said bypass flow path remaining closed until said outer assembly is landed on the support.
 11. The valve of claim 10, wherein: said valve member comprising a seat in said passage and an object that obstructs said passage when landed on said seat.
 12. The valve of claim 11, wherein: said object is retained by a retainer in said passage when separated from said seat responsive to flow from the lower end toward the upper end of said passage.
 13. The valve of claim 12, wherein: said object is a ball or a flapper.
 14. The valve of claim 9, wherein: said outer assembly further comprising spaced seals in contact with said mandrel and straddling at least one of said ports located on one side of said valve member when said bypass flow path is closed.
 15. The valve of claim 14, wherein: one of said passage ports is closed by said seals on said outer assembly when said outer assembly is not landed on the support.
 16. The valve of claim 15, wherein: said outer assembly is biased off said mandrel to a position where one of said passage ports is closed by said seals on said outer assembly.
 17. The valve of claim 16, wherein: said outer assembly comprises at least one collet and a sleeve having a recess with end seals facing said mandrel to define an annular passage at least as long as the spacing between passage ports on opposed sides of said valve member.
 18. The valve of claim 17, wherein: said at least one collet comprises a plurality of collets that are circumferentially spaced between end rings with one of said end rings comprising spaced end ring seals that selectively straddle one of said passage ports.
 19. The valve of claim 2, wherein: said bypass flow path remaining closed until said outer assembly is landed on the support. 